Does Wire Orientation Matter in the TermiLoop?
Does Wire Orientation Matter in the TermiLoop?
Short answer: For an HF radiator made from two parallel wires with a small spacer—like in the TermiLoop—the far-field radiation and polarization remain essentially unchanged whether the spacer makes the pair “vertical” or “horizontal.” What matters is the spacing-to-wavelength ratio, not whether the gap is up–down or side-by-side.
The Physics Behind It
In a folded or dual-wire element, the two conductors carry nearly equal, in-phase currents. The pair behaves as a single “thicker” conductor, and the radiation pattern is determined solely by the axis of the element. Orientation of the spacer has no effect on polarization or directivity.
Applied to the TermiLoop
Your TermiLoop spacers are roughly 20 cm. That’s a spacing ratio of:
- ≈ 0.001 λ on 160 m
- ≈ 0.01 λ on 20 m
- ≈ 0.033 λ on 6 m
All well below the 0.05 λ guideline—so whether the two wires are separated vertically or horizontally will not affect the radiation in any meaningful way. The only change is a minor ± s/2 shift in average height if you mount them vertically, which is electrically trivial at HF.
Terminated or Not—Same Result
This conclusion holds for both resonant folded dipoles and traveling-wave or terminated types (like the TermiLoop or a T2FD). The far-field pattern remains comparable to a single-wire dipole or loop of identical geometry. Spacer orientation is purely a mechanical choice.
When Orientation Could Matter Slightly
- If spacing becomes a large fraction of a wavelength (≳ 0.05 λ), the two wires begin acting like a small in-phase array, slightly shaping the pattern in the plane perpendicular to their separation.
- If the feedline carries common-mode current, the pattern can skew regardless of orientation. Always use a quality 1:1 current choke right after the UNUN, and route the coax away at right angles to the antenna leg.
Supported by Literature
L. B. Cebik (W4RNL) and other antenna theorists show that multi-wire and folded elements with equal in-phase currents behave like a single conductor of larger cross-section—the spacer’s orientation has no measurable influence on radiation characteristics.
Bottom Line
For the TermiLoop (or any similar two-wire HF radiator), small spacing means horizontal vs. vertical separation doesn’t change how it radiates. Prioritize mechanical stability, proper wire tension, and solid common-mode isolation instead of worrying about spacer direction.
Mini-FAQ
- Does the TermiLoop need to be tilted? — No. The radiation pattern follows the main wire axis, not the tilt of the spacer or loop.
- Will vertical spacing improve DX angles? — No measurable change; height and ground conditions determine take-off angle.
- Can I use different spacer materials? — Yes. Only the mechanical and dielectric strength matter; RF effect is negligible.
- What about terminated vs. open loop versions? — Both behave the same regarding orientation; termination only affects bandwidth and impedance.
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